component bw requirement of 56gbaud modulations for …

HUAWEI TECHNOLOGIES CO., LTD.

Component BW requirement of 56Gbaud

Modulations for 400GbE 2 & 10km PMD

IEEE 802.3bs 400GbE Task Force

Plenary meeting, San Diego, CA

July 14 – 18, 2014

Fei Zhu, Yangjing Wen, Yusheng Bai

Huawei US R&D Center

Santa Clara, CA 95050


Outline

Introduction – recap from May interim

Update on Nx 56Gbaud alternatives

- Sensitivity & Tolerance to MPI, w/ realistic ER

BW requirement of Nx 56Gbaud Alternatives

Summary


Readings from the straw polls of May 16 Norfolk Interim SMF duplex is clearly preferred for 400GbE 2km and 10km (Stassar_01_0614)

4A. I believe that 2km 400GbE SMF PMD will use a duplex fiber solution

Yes: 70 No: 6

4B. I believe that 10km 400GbE SMF PMD will use a duplex fiber solution

Yes: 85 No: 0

less number of optical carriers is clearly preferred for 400GbE 2km and

10km

5. For 2km duplex SMF 400GbE PMD, I believe the TF should select a proposal based on an effective

bit rate per wavelength per direction of

a) 25G: 5; b) 50G: 51; c) 100G: 77; d) 400G: 10

6. For 10 km duplex SMF 400GbE PMD, I believe the TF should select a proposal based on an

effective bit rate per wavelength per direction of

a) 25G: 5; b) 50G: 53; c) 100G: 74; d) 400G: 11


The 400GbE 2km and 10km PMD candidates

Notes:

1) “the Decision tree” (in black)

from:

Cole_3bs_01a_0514

2) 400G per l PM-16QAM option

(in blue) is proposed in

Zhu_3bs_0X_0514

3) Symbol rate (in red) is added to

highlight the focus of this

presentation --- Tx and Rx BW

requirement of Nx56Gbaud

400GbE alternatives

400GbE

PM-16QAM

400G


Nx 56Gbaud Alternatives: Sensitivity & Tolerance to MPI

Rx Sensitivity (@ BER of 1e-3, Tx/Rx 3dB BW=0.75x Baudrate, 5th order Bessel)

56Gbps NRZ 112Gbps PAM4 448Gbps PM-16QAM

No MPI -12.6 dBm - 8.4 dBm - 18.4 dBm

-30dB MPI -12.5 dBm - 7.1 dBm -18.3 dBm

-25 dB MPI - 12.2 dBm ? - 17.9 dBm

-22 -21 -20 -19 -18 -17 -16 -15 -14 -1310

-6

10-5

10-4

10-3

10-2

10-1

ROP, dBm

BE

R

No MPI

30dB MPI

25dB MPI

20dB MPI

448Gbps PM-16QAM (1x Vpi drive, ER 25dB)

-11 -10 -9 -8 -7 -6 -5 -4 -3 -210

-6

10-5

10-4

10-3

10-2

10-1

ROP, dBmB

ER

No MPI

30dB MPI

25dB MPI

20dB MPI

-15 -14 -13 -12 -11 -10 -910

-6

10-5

10-4

10-3

10-2

10-1

ROP, dBm

BE

R

No MPI

30dB MPI

25dB MPI

20dB MPI

112Gbps PAM4

(ER 6dB)

56Gbps NRZ (ER 6dB)

The difference from Zhu_3bs_0X_0514: realistic ER of 6dB is applied in simulation for IM format NRZ and PAM4.


Nx 56Gbaud Alternatives: Dependence on Rx BW

Observations:

Given a Tx BW, an optimal receiver

bandwidth exists for each format;

Optimal Rx BW for PM-16QAM, PAM4

and NRZ are similar: ~ 0.5x Symbol rate

(i.e., 3dB BW 28GHz), whether Tx 3dB

BW is set at 0.75x or 0.5x BaudRate;

PM-16QAM is less sensitive to Tx BW,

due to the nature of phase modulation. 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

-18.5

-17.5

-16.5

-15.5

-14.5

-13.5

-12.5

-11.5

-10.5

-9.5

-8.5

-7.5

-6.5-6

Receiver Bandwidth (x BaudRate)

Receiv

er

Sensitiv

ity (

dB

m)

Tx BW = 0.75 x BaudRate, PM-16QAM

Tx BW = 0.75 x BaudRate, PAM4

Tx BW = 0.75 x BaudRate, NRZ

Tx BW = 0.5 x BaudRate, PM-16QAM

Tx BW = 0.5 x BaudRate, PAM4

Tx BW = 0.5 x BaudRate, NRZ

Dashed lines: Tx 3dB BW (5th order Bessel) setting = 0.5x Baudrate, (or 28GHz);

Solid lines: Tx 3dB BW setting = 0.75x Baudrate , (or, 42GHz)


Nx 56Gbaud Alternatives: Impact of Tx BW

Nx 56Gbaud Alternatives Required Tx BW (@ Rx 3dB BW = 0.5x Baudrate)

@ 0.2dB PP @ 0.5dB PP

448 Gbps PM-16QAM 0.58x (or 32 GHz) 0.47x (or 26 GHz)

112 Gbps PAM4 0.70x (or 39 GHz) 0.56x (or 31 GHz)

56 Gbps NRZ (No Rx EQ) 0.76x (or 43 GHz) 0.60x (or 34 GHz)

Notes:

1) At optimal Rx BW of 0.5x Symbol

rate (i.e., 28GHz);

2) Rx sensitivity is defined @ BER

1e-3;

3) Power Penalty (PP) is

referenced to Tx 3dB BW of 1x

Baudrate;

4) No Rx EQ is applied in case of

NRZ;

5) No Tx pre-emphasis in all

formats considered. 0.4 0.5 0.6 0.7 0.8 0.9 1

-18.5

-17.5

-16.5

-15.5

-14.5

-13.5

-12.5

-11.5

-10.5

-9.5

-8.5

-7.5

-6.5

-6

Transmitter Bandwidth (x BaudRate)

Receiv

er

Sensitiv

ty (

dB

m)

PM-16QAM

PAM4

NRZ

0.4 0.5 0.6 0.7 0.8 0.9 10

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Transmitter Bandwidth (x BaudRate)P

ow

er

Penalty (

dB

)

PM-16QAM

PAM4

NRZ

Rx 3dB BW 0.5x Baudrate


Transmitter BW decomposed

Power

Penalty

assumed

Nx 56Gbaud 400GbE

alternatives

Total Tx 3dB BW

(5th order Bessel)

Decomposed component 3dB BW

(each component assumed 3rd order

Bessel filter, at equal contribution )

Driver Modulator

0.2 dB

448 Gbps PM-16QAM 32 GHz 45 GHz 45 GHz

112 Gbps PAM4 39 GHz 54 GHz 54 GHz

56 Gbps NRZ (no EQ) 43 GHz 59 GHz 59 GHz

0.5 dB

448 Gbps PM-16QAM 26 GHz 36 GHz 36 GHz

112 Gbps PAM4 31 GHz 43 GHz 43 GHz

56 Gbps NRZ (no EQ) 34 GHz 46 GHz 46 GHz

The above assumes no Tx analog or digital BW pre-emphasis, so it is a baseline of the fundamental

property of modulation formats;

It is possible to reduce component BW requirement with digital or analog pre-emphasis. However, pre-

emphasis could boost noise, and increase linearity requirement, in particular, for PAM4 and 16QAM;

Pre-emphasis can be quite useful. But proper noise & distortion model need to be established for proper assessment.


8x 56Gbaud NRZ: Role of Rx EQ

8x 56Gbaud NRZ

Required Tx BW

(@ Rx 3dB BW = 0.5x)

Tx 3dB BW Decomposed

(0.5dBpp, @ Rx 3dB BW=0.5x)

@ 0.2dB PP @ 0.5dB PP driver modulator

No Rx EQ 0.76x (or 43 GHz) 0.60x (or 34 GHz) 46 GHz 46 GHz

5-tap FFE only 0.72x (or 40 GHz) 0.57x (or 32 GHz) 44 GHz 44 GHz

5-tap FFE + 1-tap DFE* 0.68x (or 38 GHz) 0.51x (or 29 GHz) 40 GHz 40 GHz

Notes:

1) At optimal Rx BW of 0.5x Symbol

rate (i.e., 28GHz);

2) Rx sensitivity is defined @ BER

1e-3;

3) Power Penalty (PP) is

referenced to Tx 3dB BW of 1x

Baudrate;

4) No Tx pre-emphasis is applied.

0.4 0.5 0.6 0.7 0.8 0.9 10

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Pow

er

Penalty (

dB

)

No Equalizer

5-tap FFE Only

5-tap FFE +1-tap DFE

0.4 0.5 0.6 0.7 0.8 0.9 1-13

-12.5

-12

-11.5

-11

-10.5


Receiv

er

Sensitiv

ity (

dB

m)

No Equalizer

5-tap FFE Only

5-tap FFE +1-tap DFE


Simulation Parameters 448Gbps PM-16QAM 112Gbps PAM4 56Gbps NRZ Lyubomirsky_400_01_1113

Tx:

RIN -145 dB/Hz - 140 dB/Hz

ER 25 dB (IQ) 6 dB (IM) 4 dB

Laser LW 0.1 MHz 0.7 MHz Not available (not important)

3dB BW Variable to find minimum required @ 0.2 / 0.5dB PP 16 GHz

Filter shape 5th order Bessel 4th order Bessel

Rx:

3dB BW 0.75x & 0.5x Baudrate 0.75x Baudrate

Filter shape 5th order Bessel (PIN + TIA) 4th order Bessel

Responsibility 0.05 A/W (Cohdet) 0.85 A/W (DD) 0.4 A/W

Rx noise 30 pA/sqrt (Hz) 18 pA/sqrt (Hz)

LO LW/Power 0.1 MHz / 13dBm N/A N/A

Rx EQ 9-tap MIMO FIR 9-tap SISO FIR None/5-tap FFE/

5-tap FFE+1-tap DFE None/5-tap FFE

/5-tap FFE+1-tap DFE


Components for Nx 56Gbaud Alternatives 8 x 56Gbps NRZ 4 x 112Gbps PAM4 1x 448Gbps PM-16QAM

Lasers 8 (DML?)

(can DML still make it at 56Gbaud?) 4 (EML)

1 (shared LO) (Linewidth ~300kHz)

Modulators IM in DML or EML IM in EMLs PM-IQM

Drivers 8 (limiting) 4 (linear) 4 (linear)

Receivers & TIAs 8

(DD: single-ended PIN w/ limiting TIA)

4 (DD: single-ended PIN w/linear TIA)

1 ICR (CohDet: Optical Hybrid, 4 balanced PIN w/ linear TIA)

MUX & DeMUX optics Yes (8:1 & 1:8)

extra loss Yes (4:1 & 1:4)

extra loss N/A

Rx EQ* May be needed (to reduce Tx BW requirement)

Needed (4 A/Ds + DSP) (more tolerant to BW limit, but still sensitive to residual CD in 1310nm)

Needed (4 A/Ds + DSP) (more tolerant to BW limit &

residual CD in 1310nm)

Scalability ?? (>8 lanes lead to large CD Penalty)

?? (more lanes more MUX/DeMUM IL)

Yes ( readily scalable to 1.6TbE)

* Essentially the same table from Zhu_3bs_0X_0514, slightly updated (in red)


Summary Tx 3dB BW required (likely) of Nx 56Gbaud candidates are analyzed via simulation.

More investigations are needed to understand how much pre-emphasis or Rx EQ would help to reduce component BW requirement before specification can be reached;

The role of EQ in Tx /Rx would have direct impact on power, and would have direct impact on component cost too.

Modulation Generation/Detection

400GbE Options Max Rx Sensitivity/l

(-30dB MPI, @ BER 1x10-3)

Required Tx 3d BW (@ Rx 3dB BW=0.5x )

Tx 3dB BW decomposed

driver modulator

NRZ, IM-DD (ER=6dB) 8 x 56 Gbps -12.3 dBm/Lane 32GHz (5-tap FFE) 44 GHz 44 GHz

PAM4, IM-DD (ER=6dB) 4 x 112 Gbps -6.6 dBm/Lane 31GHz (9-tap SISO) 43 GHz 43 GHz

PM-16QAM, IQ –CohRx (1x Vpi drive, ER 25dB)

1x 448 Gbps -17.8 dBm 26GHz (9-tap MIMO) 36 GHz 36 GHz

This is not to define the specs for Tx or Rx BW, rather to clarify some “myth” about component BW

requirement for Nx 56Gbaud 400GbE alternatives, and some “myth” around power consumption.

THANK YOU

component bw requirement of 56gbaud modulations for …

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